Using normal subjects and patients with neurogenic bladder disease in rehabilitation units, this clinical nursing project will investigate if electrical impedance will measure urinary bladder volume in humans accurately and reliably. Measurements consist of rectal and abdominal skin temperatures and electrical impedance secured by a rectal probe, a skin thermistor and externally placed electrodes, respectively, for digital readout and magnetic tape recording. In addition, suprailiac and infrascapula skinfold measurements and urine volume over-time will be obtained.